getid3_dts

24class getid3_dts extends getid3_handler25{26	/**27	 * Default DTS syncword used in native .cpt or .dts formats.28	 */29	const syncword = "\x7F\xFE\x80\x01";30 31	/**32	 * @var int33	 */34	private $readBinDataOffset = 0;35 36	/**37	 * Possible syncwords indicating bitstream encoding.38	 */39	public static $syncwords = array(40		0 => "\x7F\xFE\x80\x01",  // raw big-endian41		1 => "\xFE\x7F\x01\x80",  // raw little-endian42		2 => "\x1F\xFF\xE8\x00",  // 14-bit big-endian43		3 => "\xFF\x1F\x00\xE8"); // 14-bit little-endian44 45	/**46	 * @return bool47	 */48	public function Analyze() {49		$info = &$this->getid3->info;50		$info['fileformat'] = 'dts';51 52		$this->fseek($info['avdataoffset']);53		$DTSheader = $this->fread(20); // we only need 2 words magic + 6 words frame header, but these words may be normal 16-bit words OR 14-bit words with 2 highest bits set to zero, so 8 words can be either 8*16/8 = 16 bytes OR 8*16*(16/14)/8 = 18.3 bytes54 55		// check syncword56		$sync = substr($DTSheader, 0, 4);57		if (($encoding = array_search($sync, self::$syncwords)) !== false) {58 59			$info['dts']['raw']['magic'] = $sync;60			$this->readBinDataOffset = 32;61 62		} elseif ($this->isDependencyFor('matroska')) {63 64			// Matroska contains DTS without syncword encoded as raw big-endian format65			$encoding = 0;66			$this->readBinDataOffset = 0;67 68		} else {69 70			unset($info['fileformat']);71			return $this->error('Expecting "'.implode('| ', array_map('getid3_lib::PrintHexBytes', self::$syncwords)).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes($sync).'"');72 73		}74 75		// decode header76		$fhBS = '';77		for ($word_offset = 0; $word_offset <= strlen($DTSheader); $word_offset += 2) {78			switch ($encoding) {79				case 0: // raw big-endian80					$fhBS .=        getid3_lib::BigEndian2Bin(       substr($DTSheader, $word_offset, 2) );81					break;82				case 1: // raw little-endian83					$fhBS .=        getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2)));84					break;85				case 2: // 14-bit big-endian86					$fhBS .= substr(getid3_lib::BigEndian2Bin(       substr($DTSheader, $word_offset, 2) ), 2, 14);87					break;88				case 3: // 14-bit little-endian89					$fhBS .= substr(getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2))), 2, 14);90					break;91			}92		}93 94		$info['dts']['raw']['frame_type']             =        $this->readBinData($fhBS,  1);95		$info['dts']['raw']['deficit_samples']        =        $this->readBinData($fhBS,  5);96		$info['dts']['flags']['crc_present']          = (bool) $this->readBinData($fhBS,  1);97		$info['dts']['raw']['pcm_sample_blocks']      =        $this->readBinData($fhBS,  7);98		$info['dts']['raw']['frame_byte_size']        =        $this->readBinData($fhBS, 14);99		$info['dts']['raw']['channel_arrangement']    =        $this->readBinData($fhBS,  6);100		$info['dts']['raw']['sample_frequency']       =        $this->readBinData($fhBS,  4);101		$info['dts']['raw']['bitrate']                =        $this->readBinData($fhBS,  5);102		$info['dts']['flags']['embedded_downmix']     = (bool) $this->readBinData($fhBS,  1);103		$info['dts']['flags']['dynamicrange']         = (bool) $this->readBinData($fhBS,  1);